Access user machine via WinSCP.

1. Configure WinSCP on the client PC to use the private key file
Open WinSCP and load a previously saved session, or create a new session. Enter the path and file name of the private key file in the Private key file window. I also recommend configuring WinSCP to only use the SSH2 Protocol. Click on SSH and select 2 only in the Protocol options window. Continue configuring WinSCP including an alternate Port number for the SSH server (if used) as desired then click on Save.

Legends:
Figure 1
Double click to open WinSCP configuration terminal

Figure 2
Enter the machine IP - (refer to item no.1)
Select port number to 22 for SSH (Secure Shell) - (refer to item no.2)
Enter username (admin) and SSH Key-phrase - (refer to item no.3)
Browse and enter the public SSH Key for authentication - (refer to item no.4)
Select file protocol to SFTP (Secure File Transfer Protocol) - (refer to item no.5)
Click login to continue

Legends:
Figure 3
Enter SSH Key-phrase for authentication - (refer to item no.1)